Turkish President Recep Tayyip Erdogan invoked a Muslim hadith commonly used by Hamas and other terrorist supporters to sanction killing Jews during a party convention Sunday.

“[T]hose who think they own Jerusalem better know that tomorrow they won’t be able to hide behind trees,” Erdogan’s said, according to a translation by dissident Turkish journalist Abdullah Bozkurt. Last year, Erdogan shut down Bozkurt’s former newspaper, Today’s Zaman, which had Turkey’s largest circulation.

“[This is] a veiled threat of killing each and every Jew with a shocking reference to apocalyptic prophecy of tree story,” Bozkurt wrote.

The full hadith says, “The last hour would not come unless the Muslims will fight against the Jews and the Muslims would kill them until the Jews would hide themselves behind a stone or a tree and a stone or a tree would say: Muslim, or the servant of Allah, there is a Jew behind me; come and kill him; but the tree Gharqad would not say, for it is the tree of the Jews.”

Erdogan invoked it during a Justice and Development Party (AKP) gathering days after President Trump proclaimed Jerusalem to be Israel’s capital and pledged to move the U.S. embassy there. Erdogan also accused Israel of being a terrorist state.

Erdogan is more interested in appealing to his base’s anti-Semitic sentiments than inspiring foreign jihadis to fight Israel, Bozkurt told the Investigative Project on Terrorism (IPT) via Twitter. His comments also distract the Turkish public from the New York trial of an Iranian gold trader named Reza Zarrab and Turkish banker Mehmet Hakan Atilla, who witnesses testified, worked with Erdogan to circumvent oil sanctions against Iran, Bozkurt said.

“It is a noise that will distract public from damaging revelations going on in the U.S. federal court where he was exposed for what he is: Corrupt, sanction buster, greedy politician,” Bozkurt said.

Anti-Semitism has always been in the background in Turkish society, but Bozkurt said this marks the first time Turkey’s head of state has publicly been involved with fueling it.

The Turkish Youth Foundation (TUGVA), run by Erdogan’s son, Bilal, participated in anti-Israel and anti-U.S. rallies calling on Muslims to unite against Trump’s Jerusalem announcement.

On Friday, protesters in Istanbul chanted slogans including, “Jerusalem is ours and will remain so!” and “Down with America” and “Down with Israel.”